sedimentary
Fossiliferous Limestone
Biogenic Calcium Carbonate (CaCO3)
Hardness: 3 on Mohs scale; Color: Grayish-brown with white inclusions; Luster: Dull to earthy; Crystal structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None (conchoidal fracture)
- Hardness
- 3 on Mohs scale
- Color
- Grayish-brown with white inclusions
- Luster
- Dull to earthy
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Physical properties
Hardness: 3 on Mohs scale; Color: Grayish-brown with white inclusions; Luster: Dull to earthy; Crystal structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None (conchoidal fracture)
Formation & geological history
Formed in shallow, calm, warm marine waters from the accumulation of shell, coral, algal, and fecal debris. These sediments are lithified over millions of years through compaction and cementation.
Uses & applications
Used as a building material, aggregate for road base, in the manufacture of lime and cement, and for soil conditioning in agriculture. Rare fossiliferous pieces are collected for study.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. This specific specimen contains visible bioclasts, which are fragments of ancient marine organisms.
Field identification & locations
Identified in the field by its reaction to cold dilute hydrochloric acid (fizzing) and the presence of visible fossil fragments. Commonly found in areas that were once prehistoric seafloors.
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